English
The separation quotient of X is Hausdorff if and only if X has the R1 separation property.
Русский
Узел разделения кватернения X является Hausdorff тогда и только тогда, когда X обладает свойством разделения R1.
LaTeX
$$$ \operatorname{t2Space\_iff}(X) \iff \operatorname{R1Space}(X) $$$
Lean4
theorem t2Space_iff : T2Space (SeparationQuotient X) ↔ R1Space X := by
simp only [t2Space_iff_disjoint_nhds, Pairwise, surjective_mk.forall₂, ne_eq, mk_eq_mk,
r1Space_iff_inseparable_or_disjoint_nhds, ← disjoint_comap_iff surjective_mk, comap_mk_nhds_mk,
← or_iff_not_imp_left]